Device for sterilizing packaging using hydrogen peroxide

ABSTRACT

Described is an apparatus for simultaneously sterilizing a large number of packs ( 1 ) by means of a gas mixture containing hydrogen peroxide and a carrier gas. The apparatus comprises: supply lines ( 4 ) for the carrier gas and for hydrogen peroxide ( 5 ), a device ( 21 ) for evaporating hydrogen peroxide by heat and mixing it into the carrier gas, supply lines ( 4, 5 ) and a substantially horizontally extending distributor line ( 6, 22 ) and nozzles ( 3 ) which are arranged above the respective pack ( 1 ) and are connected to the distributor line ( 6, 22 ). In order simultaneously to provide, with a simplification in the apparatus, measures by means of which the concentration of the hydrogen peroxide at all nozzles is maintained equal over the plurality of packs at a given time, the invention provides that the distributor line ( 6, 22 ) from the upstream location ( 23 ) of the in-feed of the conditioned gas mixture to the location ( 9 ) of entry upstream of the respective nozzle ( 3 ) is in the form of a tubular body including a longitudinal passage, with at least one substantially tubular heating cartridge ( 18 ) extending over the length of the tubular body and distributed measurement points ( 12 ) and that the heating cartridge ( 18 ) is divided into at least two portions and can be heated controlledly by a supply of electrical energy in such a way that the temperature at the outer ends of the tubular body ( 6 ) differs from the temperature at the center.

This application is a 371 of PCT/EP01/08779 filed Jul. 28, 2001.

The invention concerns an apparatus for simultaneously sterilizing amultiplicity of packs by means of a gas mixture containing hydrogenperoxide and a carrier gas, comprising

supply lines for the carrier gas and for hydrogen peroxide,

a device for evaporating hydrogen peroxide with heat and for mixing itinto the carrier gas,

supply lines and a substantially horizontally extending distributorline, and

nozzles which are arranged above the respective pack and are connectedto the distributor line.

It is known for upwardly open packs to be sterilized by introducing amixture of air and gaseous hydrogen peroxide. With that known process aplurality of packs which are arranged in mutually side-by-siderelationship in a row are simultaneously passed under the openings of acorresponding number of nozzles. The sterilization gas mixture isproduced by hot air being passed through a porous tubular portionthrough which completely evaporated hydrogen peroxide is urged from theexterior and then mixed with the air. In addition, to avoid condensationof the sterilization agent, the mixture is passed through a supply anddistributor line which is of a double-wall configuration and is chargedwith hot vapor.

The configuration of the lines with heated tube walls is expensive anddifficult and complicated to produce and diffusion of the evaporatedhydrogen peroxide in the sintered tubular member into the hot air alsoinvolves problems because very high pump pressures are required for thehydrogen peroxide and it is necessary to take precautions to ensure thatpores of the right size are not blocked. Clogging of the pores can beexpected when small pore sizes are involved while when excessively largepores are used the hydrogen peroxide is only inadequately evaporated.

Therefore the object of the present invention is to simplify theapparatus of the kind set forth in the opening part of thisspecification and at the same time to provide measures for keeping theconcentration of hydrogen peroxide identical at all nozzles over theplurality of packs at a given time.

In accordance with the invention that object is attained in that thedistributor line from the upstream location of the in-feed of theconditioned gas mixture to the location of entry upstream of therespective nozzle is in the form of a tubular body containing alongitudinal passage, with at least one substantially tubular heatingcartridge extending over the length of the body, and distributedmeasurement locations, and that the heating cartridge is divided into atleast two portions and can be heated controlledly by a supply ofelectrical energy in such a way that the temperature at the outer endsof the tubular body differs from that at the center and that preferablythe temperature at the ends can be adjusted independently from thetemperature at the center.

By virtue of the invention, in comparison with the state of the art, itis no longer necessary for the distributor line or indeed also thesupply line to be of a double-wall configuration for heating thepipeline by means of passing hot vapor therethrough. It is sufficient touse a longitudinal passage with a heating cartridge which is arranged inthe longitudinal direction thereof, in order to build up a giventemperature profile in the longitudinal passage. It is understandablyeasier to provide a single-wall longitudinal passage or to provide samein a tubular body and at the same time arrange heating cartridges there.It has been found that it is also more desirable if the gas mixture,after it has been produced and introduced into the distributor line, isheated in the latter by means of heating cartridges, especially as atemperature profile of the desired magnitude is quite easy to build up,in accordance with the division of the heating cartridge into at leasttwo portions. It was surprisingly found that the temperature of the gasmixture at the distributor line and in particular at the ends thereofcauses a variation in the concentration of the peroxide in the gasphase. Therefore it is particularly preferred in accordance with theinvention for the temperature at the outer ends of the tubular body tobe lower than at the center thereof. By means of suitable heating of theheating cartridge in the center of the tubular body, it is possible tocounteract a reduction, that is to say cooling of the gas mixture, atthe necessary locations, with the consequence that the temperature atthe outer end regions of the tubular body is lower than at the centralregion thereof, thereby surprisingly achieving both a temperature, whichremains the same everywhere, of the gas mixture flowing out of thetubular body, and also a concentration, which remains the sameeverywhere, of the H₂O₂ contained therein.

With the sterilization apparatus according to the invention it ispossible to simultaneously sterilize 5, 10 or 20 packs, that is to sayto act thereon with the sterilization gas through the nozzles. As in theknown case the packs to be sterilized are arranged in a row which ispreferably in a straight line. The tubular body representing thedistributor line then extends over that row of packs, that is to say itis in the form of an elongate rail or an elongate passage. Preferablythe gas mixture produced is introduced at the center of the longitudinalextent of the tubular body and the latter is heated in such a way thatthe temperature of the gas decreases towards the outer ends of thetubular body. The invention provides for heating of the walls of thelongitudinal passage in the central region and possibly also the entiretubular body in comparison with the outer ends thereof although thein-feed location of the gas mixture is in the central region. Inaccordance with the invention that avoids irregular heating anddistribution of the concentration of the peroxide in the gas mixture.

In a specific preferred embodiment packs of a capacity of 0.5 liter, 1liter and 1.5 liters have been respectively sterilized at the same timein tens. The overall volume flow of air for each 10 bottles was between20 and 30 Nm³/h and particularly preferably 22 Nm³/h. The temperature ofthe air should be in the range of between 110° and 150° C. and shouldparticularly preferably be 140° C. 25% hydrogen peroxide was meteredlyadded in liquid form per cycle, that is to say for each 10 bottles, morespecifically for the 0.5 liter pack between 0.5 and 1.0 ml, preferably0.75 ml; for a 1 liter pack: between 1.0 and 1.5 ml, preferably 1.0 ml;and for a 1.5 liter pack: between 1.75 and 2.5 ml and particularlypreferably 2.0 ml. As the volume flow for liquid hydrogen peroxide, avalue of between 1.5 and 1.9 ml/s and particularly preferably 1.7 ml/sshould be used. The gas concentration was in the range of between 50 and93 g H₂O₂/Nm³ air and in particular in a desirable example it was 77 gH₂O₂/Nm³ of air.

In an advantageous configuration of the invention the tubular body is inthe form of an elongate bar with a strong main body through whichcentrally passes a longitudinal bore forming the gas passage, withcommunicating openings to the nozzles, and which on opposite sides ofthe gas passage and at a spacing in relation to the gas passage isprovided with outwardly open grooves for the insertion of a heatingcartridge. Production of the distributor line is particularly simplewith those measures for a tubular body which is built up in that way canbe easily manufactured from a bar-like strong main body. It is onlynecessary to centrally provide a longitudinal bore in the longitudinaldirection of the bar, the bore being provided with communicatingopenings, corresponding to the number of intended nozzles, transverselywith respect to the longitudinal direction of the bar. The nozzles arethen fitted in the region of those communicating openings, for example“underneath”, on the tubular body and the main body because thesterilization gases and also other treatment agents in subsequenttreatment stations of the overall machine are desirably introduced fromabove downwardly and, after having acting on the surfaces of theinternal walls of the packs, can be sucked away upwardly again.Therefore the tubular body is arranged above the nozzles and they aredisposed above the packs to be treated.

While the communicating openings with the nozzles are then provided inthe bottom of the main body, in accordance with the invention arespective outwardly open groove is also arranged at opposite sides,that is to say laterally of the tubular body and the main bodyrespectively, because one or more heating cartridges is/are then to beparticularly easily arranged beside the longitudinal bore. In an outwarddirection clamping and pressure portions provide for closure andinsulation in relation to dissipation of heat.

It is particularly desirable in accordance with the invention if eachportion of the heating cartridge is heatable independently of the other.Such independent regulation of individual heating cartridge portions oreach heating cartridge portion in relation to the adjacent portion meansthat it is possible to adjust the desired temperature profile, with theconsequence that for example the temperature in the tubular body fallsfrom the center outwardly. If, in the case of an apparatus whichincludes those features according to the invention, the temperature ismeasured at the respective nozzle end, then regulation is possible insuch a way that the temperature of the gas at the nozzle end, at themoment of flowing out of same for the sterilization procedure, is thesame in relation to all packs of the row which is just being treated.This means that the level of concentration of hydrogen peroxide is thesame in all packs, with the consequence of identical sterilization.

It is further desirable in accordance with the invention if therespective nozzle is connected, preferably by way of a nozzle holdingplate, to the communicating openings of the tubular body and is mountedto the latter and has a throttle opening. That throttle opening can beformed in different ways. It is disposed for example at the upstreamintake side of the nozzle while the so-called spray holes are at thedownstream end of the nozzle; in the case of a normal elongate nozzlethere is a single spray hole. In the case of the last-mentionedembodiment of the elongate nozzle the throttle opening can even beidentical to the spray hole and can be at the nozzle end. In anotheralternative embodiment in contrast the throttle opening can be at theupstream side and at a spacing from the nozzle end. In each embodimenthowever the respective nozzle should be provided with a throttle openingin order to cause a back-up of the gas mixture with the consequence thatthe throttling action and thus the pressure drop over the length of thegas passage are negligibly small. In contrast the throttle opening ofthe nozzle should produce a substantially greater pressure drop. In thatway the volume flow of the gas mixture issuing from each nozzle is alsoinfluenced and is substantially identical when the teaching according tothe invention is observed.

The apparatus according to the invention can be used to sterilize bothupwardly open packs in the interior and also upwardly closed packs atthe outside surface thereof. In the former case the throttle opening atthe nozzle end can be downward while the openings and lines which aredisposed upstream thereof have a substantially smaller throttle actionbecause the passage openings are larger.

In the case of the second-mentioned embodiment in which for example apack in the form of a bottle is still closed in its upper screwthreadedneck region and is sterilized from the exterior, equality of the volumeflows issuing from the individual nozzles is achieved by a throttleopening in an aperture plate which is arranged in the region of theentry location of the conditioned gas mixture between the distributorline and the nozzle. That entry location can preferably be in the regionof the respective communicating opening to the nozzles.

In that embodiment of the sterilization apparatus according to theinvention, in which upwardly open packs are sterilized in the interiorthereof, the respective nozzle of the nozzles which are disposed fixedin a row under the tubular body is provided with a fixing flange at thetop for mounting to a nozzle holding plate and with a further elongatethrough-flow passage which extends approximately over two thirds of thenozzle length, and in the region of the nozzle end with a narrowerdischarge passage which at the same time performs the function of thethrottle opening. In this embodiment the edge of the respective upwardlyopen pack is held vertically at a spacing below the lower nozzle end. Inthat way the packs can be transported horizontally past the nozzlestherebeneath. Annular suction devices can also be provided at the outerperiphery of the lower nozzle end in order to receive, suck away andcarry off the discharge gases which issue from the interior of the packswhich have been subjected to the action of sterilizing gas.

There are also packs which are in the form of a bottle and which at thetop have an opening on the bottle neck, which is provided with a malescrewthread. In the production of such bottles which usually compriseHDPE and are produced by an extrusion blow molding process the bottle isinternally sterile after manufacture and the opening at the bottle neckat the top is still closed in that intermediate stage by a dome which iscut off in a later processing station. In the region of the cut, nocontamination is to pass into the interior of such a pack. It istherefore preferable to sterilize the external surfaces in the region ofthe bottle neck and the dome thereabove, while the pack is still in aclosed condition. Accordingly, in accordance with the invention, thenozzle has an internal space which at least partially embraces theregions of the pack to be sterilized and which is delimited by achannel-shaped spray passage which is open on opposite sides andprovided with spray holes, and outside walls which are arranged at aspacing from the spray passage and which are also laterally partiallyopen. It has already been mentioned above that, in this embodiment, thethrottle opening of the nozzle is at the top at the entry location ofthe conditioned gas mixture in the region of the communicating opening.The above-mentioned annular spray passage is disposed at a spacing fromthe above-mentioned throttle opening or aperture beneath and withinoutside walls and at a spacing therefrom. The spray passage is providedwith spray holes in that region in which the pack to be sterilized comesto a stop for the treatment. In other words, the spray holes areadmittedly at least partially also in the channel at the top, butpreferably and primarily on opposite sides of the channel walls. On theother two sides the channel is open on opposite sides, and for thatreason this involves a spray passage in the form of a channel. Morespecifically, the upper closed part of the pack engages into thatchannel and is passed along the channel, intermittently stopped in theregion of the spray holes and then continues its movement, depending onwhen the row of packs is moved to the nozzle and further conveyed alongafter treatment.

For the treatment of this embodiment of the upwardly closed packs,preferably the bottles which are still closed at the top at the bottleneck with a dome, the upper region of that pack engages into thechannel-shaped spray passage. That spray passage delimits the internalspace into which the upper part of the pack engages, in which case theinternal space therefore embraces the upper part of the pack. The upperpart of the pack is to be externally sterilized. The external walls ofthe nozzle are disposed at a spacing from the channel walls of the spraypassage outwardly transversely with respect to the longitudinaldirection of the channel so that a space is respectively formedoutwardly behind the spray nozzles, through which space the conditionedgas mixture can be passed from the upstream region of the nozzle throughthe spray holes to the pack surface which is to be sterilized.

After the spraying operation the gas mixture which has been used upflows away outwardly on the one hand at the lower edge of the spraypassage, preferably above a bottle holding plate if such is provided,and also flows away outwardly along the spray passage. There thecomponent of the gas mixture which has either not been used or consumedcan be drawn off and collected for re-processing.

It is further desirable in accordance with the invention if the devicefor evaporating hydrogen peroxide with heat and for mixing it into thecarrier gas has an atomization nozzle which is fed by a supply line forliquid hydrogen peroxide and which is arranged in the central region ofan evaporation chamber upstream of a heating body, to the upstream hotsurface of which hydrogen peroxide is fed in mist form with mixing withhot carrier gas and is passed through passages into the heating body insuch a way that super-heating of the gas mixture is effected beforebeing fed into the distributor line. Therefore, to produce and conditionthe sterilizing gas mixture, gaseous hydrogen peroxide is mixed withcarrier gas, preferably hot sterile air, and then fed to the respectivenozzle. That procedure for producing and conditioning the gas mixture isinitially effected centrally in the above-mentioned evaporation andmixing device. In the preferred embodiment which is being discussedhere, the evaporation and mixing device is a heating body with anevaporation chamber connected upstream thereof. Hot air is supplied byway of pumps to the evaporation chamber which for example can be mountedlike an inverted funnel on a flat hot surface of the heating body.Disposed approximately at the center of that evaporation chamber is thedownstream end of an atomization nozzle to which liquid hydrogenperoxide is fed. That H₂O₂ mist is firstly mixed with the hot air andthen passes onto the above-mentioned flat hot surface, evaporates and isfinally heated in the passages in the heating body. Thereafter the gasmixture is conditioned and can be fed centrally to the tubular body andthereafter along same to the individual nozzles.

In the case of such a conditioning process the sterilizing agent isfirstly sprayed onto the above-mentioned hot surface which is at a firsttemperature. That surface is smaller than that at which film boilingbegins. More specifically the gas mixture is deposited in the form of afilm and then begins to boil on those surfaces. The heating body permitssuper-heating of the sterilizing agent which is passed downwardly fromthe above-mentioned hot surface along the passages in the heating body.In counterflow relationship therewith, that is to say from belowupwardly, a heat flow can be produced in the heating body, whichprovides for the super-heating effect.

For that purpose it is desirable if, in accordance with the invention,some heating bars are inserted in the downstream end region of theheating body.

With the sterilizing apparatus according to the invention thesterilizing agent—as mentioned hereinbefore—is brought into contact withthe upper hot surface of the heating body by being sprayed thereon inmist form. It is therefore not a liquid (the sterilizing mixture) thatcomes into contact with the upper hot surface, but only a mist of thesterilizing agent, that is to say a large number of finely distributeddroplets. That provides that the effective surface area of the liquidsterilizing agent is considerably increased and the transfer of heatfrom the hot surface to the respective liquid droplet improved.

So that atomization at the end of the atomization nozzle can besuccessfully implemented, a further configuration of the inventionprovides that the supply line for liquid hydrogen peroxide is cooled bya cooling fluid. Preferably the atomization nozzle which is of anelongate configuration and which extends from its supply location intothe center of the evaporation chamber can be externally provided with acasing through which coolant, for example water, flows. The technicalproduction of such an externally cooled elongate nozzle can besatisfactorily managed without problems.

The insertion of tubular heating bars, for example from below into thedownstream end region of the heating body, is also technically free fromproblems. It is possible in that way to produce a thermal gradient frombelow upwardly and thus a flow of heat in the heating body which is inopposite relationship to the flow of the gas mixture undergoingevaporation. In that way it is possible to achieve effectivesuper-heating of the sterilizing gas, with sparing use of energy. Inthat respect consideration should always be given to the recommendationaccording to the invention that the downstream end of the atomizationnozzle is disposed at a spacing from the walls of the evaporationchamber, that is to say the hydrogen peroxide mist is not sprayed onto awall but is sprayed freely into the space of the evaporation chamber.

Even if PET and HDPE packs are sterilized by means of hydrogen peroxidethe existing hygiene and health conditions are satisfied. It is possibleto keep the residual H₂O₂ amount in PET-bottles filled with liquid below0.5 ppm.

In regard to the manufacture, sterilization, filling and closure ofpacks using the apparatus according to the invention, in the case of aparticularly preferred powerful machine, the cycle time involved wasabout 5.7 seconds, including the transportation time from one station toanother. The respective pack is therefore resident for between about 4.5and 5.5 seconds under the nozzle, in a specific embodiment that time was4.7 seconds.

At the ends of ten nozzles arranged in succession in a row, temperatureswere attained which deviated less than 10° C. from each other, withhighest temperatures of 143° C. and lowest temperatures of 134° C. in apreferred embodiment.

Further advantages, features and possible uses of the present inventionwill be apparent from the description hereinafter with reference to theaccompanying drawings in which:

FIG. 1 is a diagrammatic overview of a sterilizing apparatus, showing inparticular the distributor line with the downwardly projecting nozzlesand in the center projecting upwardly the heating body,

FIG. 2 is an isometric representation of the elongate tubular body withthe heating body which is mounted in such a way as to project centrallyupwardly, the evaporation chamber arranged thereabove and the supplylines,

FIG. 3 shows a vertical longitudinal section through the apparatus ofFIG. 2,

FIG. 4 shows a broken-away horizontal section of the right-hand half ofthe tubular body,

FIG. 5 shows a longitudinal cross-section through a heating cartridgewith three zones,

FIG. 6 shows a cross-sectional view of the tubular body, the sectionplane being perpendicular to the plane of the paper in FIG. 3,

FIG. 7 shows a nozzle of a particular embodiment with channel-shapedspray passage for blowing sterilizing gas onto the external surface ofthe upper part of a pack,

FIG. 8 shows a broken-away cross-sectional view through the nozzle ofanother embodiment for blowing conditioned gas into the interior of apack through the upper opening thereof, and

FIG. 9 shows a partly broken-away side and cross-sectional view of anatomization nozzle.

In the case of the preferred embodiments illustrated in the drawings,for the simultaneous sterilization operation, ten packs 1 are arrangedin a row in succession as shown in FIG. 3 under a respective nozzle 2 or3. Sterile hot air as a carrier gas on the one hand and liquid hydrogenperoxide on the other hand are passed by way of supply lines 4, 5 to adevice 21 for evaporation of the hydrogen peroxide with heat and formixing it into the hot air so that the conditioned gas mixture canfinally be passed into the distributor line generally identified byreference numeral 22 and from there into the nozzles 2, 3. From theupstream location 23 for the in-feed of the conditioned gas mixture, itpasses through the distributor line 22 from the location 23 arranged atthe center of the distributor line 22 in the left-hand half shown inFIGS. 1 through 3 towards the left and in the right-hand side towardsthe right to the left and right outer ends respectively of thedistributor line 22.

The distributor line 22 is designed as a tubular body 6 in the form ofan elongate bar. As shown in FIGS. 4 and 6 the latter comprises a strongmain body 7 through which there centrally passes an elongate passage 8which is in the form of a gas passage. The passage can be produced byboring through the main body 7 in the longitudinal direction. Therefore,the longitudinal passage 8 is shown as the gas passage in FIG. 6 asbeing of round cross-section. FIG. 4 is a view onto the lowerhalf-channel of the longitudinal passage 8 and it is possible to see,arranged at a spacing from each other, five communicating openings 9which provide for a direct communication with the nozzles 2 and 3respectively which are mounted to the communicating openings 9. A nozzleholding plate 11 can be fixed in coincident relationship with thosecommunicating openings 9 under the bottom 10 of the tubular body 6. Thenozzles 2, 3 are mounted to the nozzle holding plate 11 by suitablemeans.

Referring to FIG. 1 it will be seen that provided distributed over thelength of the tubular body 6 are measuring locations 12 in the form oftemperature sensors, the outputs of which can be seen in FIGS. 2 and 3as being passed upwardly. The tubular body 6 is monitored both at itsright-hand half and also at its left-hand half at three locations by wayof the temperature measuring locations 12, for which reason in FIG. 1when dividing the tubular body 6 into “left” and “right”, on each side,three temperatures are measured, more specifically Tr inner, Tr centraland Tr outer. The same also applies in regard to “left”, which isindicated by the letter “l”.

Also provided for any pressure measurement procedure are openings whichare closed by end plugs 14 and through which pressure measurementsensors can be introduced, although they are not shown here. Inter alia,as shown in FIG. 1, the temperature of the heating effect can bemeasured at the evaporation device 21 in the upper region and thetemperature of the discharge air can be measured in the lower region.The temperature of the sterile hot air, the feed air, can also bemeasured in the supply line 4, in which respect the through-flow meter15 which is more clearly shown in FIGS. 2 and 3 is only diagrammaticallyindicated here. It will be appreciated that the through-flow rate of hotair can be regulated by valves 16.

The tubular body 6 with the main body 7 through which the longitudinalpassage 8 passes has, on the outward sides which are indicated at rightand left in FIG. 6 and at top and bottom in FIG. 4, outwardly opengrooves 17 into which a respective elongate heating cartridge 18 can befitted from the exterior in the production procedure. As there is arespective groove 17 on each of the two sides of the longitudinalpassage 8 it is therefore possible overall to insert two heatingcartridges. As shown in FIGS. 2 and 3 the two heating cartridges 18protrude by a portion towards both sides (right and left), as can beseen on an enlarged scale in the plan view in FIG. 6 in respect of theright-hand end. The heating cartridge 18 is shown on an enlarged scalein cross-section in FIG. 5 with its electrical connection 19 at one end,preferably the end which protrudes from the tubular body 6. In itsentirety the heating cartridge 18 is subdivided into three portions 18a, 18 b and 18 c and each portion 18 a, 18 b, 18 c is provided with itsown electrical connection 19 so that the three respective temperatureregions on each half of the elongate tubular body 6 can be controlledand heated differently.

Moreover, after insertion of the heating cartridges 18, pressureportions 32 are fitted from the exterior into the laterally open grooves17 of the tubular body 6 and clamped fast by means of clamping plates 33with pressure screws 34.

A first embodiment of a nozzle which is identified by reference numeral3 is shown in FIGS. 3 and 7. Flat or curved outsides walls 24 extenddownwardly from an annular fixing flange 20 which has the communicatingopening 9 at the top, thus affording an elongate space for theconditioned gas mixture to flow in, in a downward direction. The outsidewall 24 is provided at its bottom with an end edge 25 to which a spraypassage 26 is fixed. The latter is in the form of a channel and, likethe space which externally surrounds that channel and which is delimitedby the outside walls 24, is open forwardly and rearwardly in thedirection of viewing FIG. 7 and in the opposite direction thereto. Inthis embodiment, in that direction which is perpendicular to the planeof the paper in FIG. 7, packs which are in the form of HDPE bottlesclosed at the top by a dome can be intermittently moved. The packs eachstop under a respective nozzle or in a nozzle region in which the spraypassage 26 is provided with spray holes 27.

The channel-shaped spray passage 26 provides a channel-shaped internalspace 28 through which the upper part of the upwardly closed pack 1passes so that gas mixture which passes into the internal space 28through the spray holes 27 passes onto the surfaces of the upper part ofthe pack 1 and sterilizes those surfaces. Discharge gas which has notbeen used or consumed then flows in the internal space in the directionof viewing FIG. 7 perpendicularly to the paper or in oppositerelationship to that direction of view and downwardly in the directionof the curved arrow 29 and away into the surroundings. There thedischarge gas can be collected. In the case of a bottle holding plate(not shown), the pack 1 hangs in recesses (not shown) in the plate, sothat the discharge gases flow away to the side by way of the bottleholding plate, and can be caught there.

To improve the back-up effect, provided at the upper end in the regionof the fixing flange 20 beside the communicating opening 9 is arestrictor disk 30 in the form of an aperture plate with a hole. Thathole predetermines a throttle opening 31.

An alternative embodiment of a nozzle identified by reference numeral 2is shown in FIG. 8. It hangs by way of a fixing flange 20′ in the nozzleholding plate 11 and is fixed there. The main extent of that elongatenozzle 2 is substantially vertical, and for that reason the nozzle 2extends from above downwardly and projects downwardly out of the nozzleholding plate 11. Over between approximately two thirds and threequarters of the total length of the nozzle 2, passing therethrough is athrough-flow passage 35 of larger diameter, in comparison with thedischarge flow passage 36. The two passages 35 and 36 are disposed inmutual alignment. For this second embodiment of the nozzle 2, thedischarge flow passage 36 forms the throttle opening so that thepressure drop in respect of the conditioned gas mixture, between theinterior of the tubular body 6 and the surroundings, is producedpredominantly in the region of the discharge flow passage 36. The secondembodiment of the elongate nozzle 2, which is shown in FIG. 8, servesfor introducing the sterilizing gas mixture substantially verticallydownwardly into a pack 1 which in the form of a PET bottle and which isopen at the top and the uppermost edge 37 of which is held at a spacinga from the lower edge 38 of the nozzle 2.

FIG. 9 is a perspective and partially cross-sectional view showing theatomization nozzle which is generally identified by reference 39 andwhich at its upper end communicates with the supply line 5 for liquidhydrogen peroxide while the space around the lower region of theatomization nozzle 39 is in communication with the supply line 4 forheated sterile air. It is possible to see here the substantiallyvertically extending flow passage 40 for liquid hydrogen peroxide whichremains in liquid phase until it passes into and out of the actualatomization nozzle which is here identified as the lower end 41. Forthat purpose the nozzle body 42 forming the flow passage 40 isexternally surrounded by a double chamber 43, 44, whose inner part 43,besides the lower end 41, is in flow communication with the outer part44 of the double chamber. In addition the inner part 43 of the doublechamber is in flow communication at the top with a water feed 45 andtherebeside the outer part 44 is in flow communication with a waterdischarge 46. If a cold water conduit is connected to the water feed 45then the nozzle body 42 can be cooled by the cold water which flows intothe arrangement. That cold water flows vertically downwardly along thenozzle body 42, there passes into the outer part 44 of the doublechamber and flows coaxially upwardly to leave the outer part 44 of thedouble chamber through the water discharge 46.

The lower end 41 of the atomization nozzle 39 is disposed approximatelyin the central region of an evaporation chamber 47 which is shown asbeing of frustoconical configuration. The enlarged part of the truncatedcone is connected by way of an annular flange 48 to the upstream topside of a heating body 49. Hydrogen peroxide in mist form, mixed withthe hot air, is fed substantially from above downwardly to the upstream,hot, flat surface 50 of the body 49. In that way the carrier gas (hotsterile air) mixed with the mist is already evaporated at that surface50. The evaporated gas mixture then flows vertically downwardly throughpassages 51 which extend parallel to each other and which passsubstantially vertically and completely through the heating body 50 andwhose hot outside walls provide for further warming and possiblysuper-heating of the gas mixture. Inserted along the heating body 49 isa ring of heating bars 52 whose electrical supply lines 53 are shown asprojecting radially or at one or more sides (FIG. 2).

List of references  1 pack 2, 3 nozzle 4, 5 supply line  6 tubular body 7 main body  8 longitudinal passage  9 communicating opening 10 bottomof the tubular body 6 11 nozzle holding plate 12 measuring location 13output of the temperature sensor 14 end plugs 15 through-flow meter 16valve 17 groove 18 heating cartridge 19 electrical connection 20, 20′fixing flanges 21 evaporation device 22 distributor line 23 upstreamfeed-in location 24 outside wall 25 end edge 26 spray passage 27 sprayhole 28 internal space 29 flow direction of the discharge gas 30restrictor disk 31 throttle opening 32 pressure portions 33 clampingplate 34 pressure screw 35 through-flow passage 36 discharge flowpassage 37 uppermost edge of the open pack 38 lower edge of the nozzle 239 atomization nozzle 40 flow passage 41 lower end 42 nozzle body 43double chamber, inner part 44 double chamber, outer part 45 water feed46 water discharge 47 evaporation chamber 48 annular flange 49 heatingbody 50 hot surface 51 passage 52 heating bar 53 electrical supply linea spacing

What is claimed is:
 1. Apparatus for simultaneously sterilizing amultiplicity of packs (1) by means of a gas mixture containing hydrogenperoxide and a carrier gas, comprising supply lines for the carrier gas(4) and for hydrogen peroxide (5), a device (21) for evaporatinghydrogen peroxide with heat and for mixing it into the carrier gas,supply lines (4, 5) and a substantially horizontally extendingdistributor line (6, 22), and nozzles (2, 3) which are arranged abovethe respective pack (1) and are connected to the distributor line (6,22), characterized in that the distributor line (6, 22) from theupstream location (23) of the in-feed of the conditioned gas mixture tothe location (9) of entry upstream of the respective nozzle (2, 3) is inthe form of a tubular body (6) containing a longitudinal passage (8),with at least one substantially tubular heating cartridge (18) extendingover the length of the body, and distributed measurement locations (12),and that the heating cartridge (18) is divided into at least twoportions (18 a, 18 b, 18 c) and can be heated controlledly by a supplyof electrical energy in such a way that the temperature (T) at the outerends of the tubular body (6) differs from that at the center. 2.Apparatus as set forth in claim 1 characterized in that the tubular body(6) is in the form of an elongate bar with a strong main body (7)through which there centrally passes the longitudinal passage (8)forming the gas passage (8) with communicating openings (9) to thenozzles (2, 3) and which is provided on opposite sides of the gaspassage (8) and at a spacing with respect thereto with outwardly opengrooves (17) for the insertion of a heating cartridge (18).
 3. Apparatusas set forth in claim 1 characterized in that each portion (18 a, 18 b,18 c) of the heating cartridge (18) is heatable independently of theother.
 4. Apparatus as set forth in claim 1 characterized in that therespective nozzle (2, 3) is connected preferably by way of a nozzleholding plate (11) to the communicating openings (9) of the tubular body(6) and is mounted to the latter and has a throttle opening (31, 36). 5.Apparatus as set forth in claim 1 characterized in that the nozzle (3)has an internal space (28) which at least partially embraces the regionsof the pack (1) to be sterilized and is delimited by an annular spraypassage (26) which is open on opposite sides and which is provided withspray holes (27) and outside walls (24) which are disposed at a spacingfrom the spray passage (26) and which are also laterally partially open.6. Apparatus as set forth in claim 1 characterized in that the devicefor the evaporation of hydrogen peroxide with heat and for mixing itinto the carrier gas has an atomization nozzle (39) which is fed by asupply line (5) for liquid hydrogen peroxide and which is arranged inthe central region of a evaporation chamber (47) upstream of a heatingbody (49), to the upstream hot surface (50) of which hydrogen peroxideis fed in mist form with mixing with hot carrier gas and is passedthrough passages (51) into the heating body (50) in such a way thatsuper-heating of the gas mixture occurs prior to being fed into thedistributor line (6, 22).
 7. Apparatus as set forth in claim 6characterized in that some heating bars (52) are inserted at least inthe downstream end region of the heating body (49).
 8. Apparatus as setforth in claim 6 characterized in that the supply line (5) for liquidhydrogen peroxide is cooled by a cooling fluid.